1. Field of the Invention
The subject invention relates to automated manufacturing equipment in the style of an assembly line. More particularly, the invention concerns a filling preparation station that produces defined lengths of meat or other filling materials and precisely places the filling material upon tortillas for the manufacture of taquitos, enchiladas, burritos, and other rolled, folded, or wrapped tortilla foods.
2. Description of the Related Art
For many years, the food manufacturing industry has been a productive source of technological innovation. Without the use of machines, the manufacturing of food products can require an enormous amount of repetitive labor. Although human workers are frequently needed to supervise, correct, and even perform many steps in the food manufacturing process, today""s factories are using machines in greater numbers to complete tasks that are amenable to automated performance.
The Mexican food industry is no exception to the current trend. One example of automation in the Mexican food industry appears in the assembly of filled tortilla products such as xe2x80x9ctaquitosxe2x80x9d (also known as xe2x80x9crolled tacosxe2x80x9d), burritos, enchiladas, quesadillas, and the like. Each of these products comprises a tortilla that is wrapped, rolled, or folded about an internal xe2x80x9cfillingxe2x80x9d material, such as meat, cheese, beans, and/or rice, etc. One early technical innovation in creating filled tortilla products has been the use of an extrusion machine to create filling segments of desired sizes. This extrusion machine places its filling segments upon a conveyor belt. Human hands remove filling segments from this conveyor belt, center the filling segments on tortillas arriving on a different conveyor belt, and roll, fold, or wrap the tortillas about their filling segments.
As an improvement to this product line, another known technique changed the process of creating and depositing the filing material. This technique employs a pulsed, volumetric extruder to create the filling segments. The extruder""s nozzle is positioned to generate filling segments directly onto the tortillas arriving on their conveyor belt. After a filling portion is deposited on a tortilla, a human worker removes the filling and tortilla onto a platform, repositions the filling, rolls, folds, or wraps the tortilla about the filling segment, and places the completed product on an output conveyor belt leading to a fryer, freezer, or other processing device. This arrangement provided some benefit because it uses the extruder to initially place filling material onto tortillas, saving the cost of having human laborers perform this task.
Nonetheless, there are still a number of remaining challenges to those people interested in a more automated assembly line. One such challenge is in reducing variance in the sizes of the filling segments, since filling segments must include a minimum volume according to eventual package labeling. Therefore, in order to guarantee this minimum volume, the extruder must be adjusted to generate slightly larger filling pieces to account for the possibility of errant, small pieces. Whenever the size of a filing piece exceeds the designated minimum volume, however, the excess product incurs an excess cost. Accordingly, a significant challenge exists in the area of automatically controlling product size.
There are still other challenges in automated manufacturing of Mexican food. Even though the conventional approach initially places the filling material on the tortillas, workers are still needed to reposition the filling material because automated placement is not always accurate. Inaccurate placement is undesirable for various reasons, such as the creation of an unattractive and unappetizing product. In addition, if automated machinery places the filling material so poorly that it protrudes from the tortilla, the filling material could contaminate downstream processing equipment if this protruding filling material breaks off. Moreover, if poorly placed filling material misses its intended tortilla to create an unfilled tortilla, the tortilla can excessively absorb fryer oil, depleting the oil earlier than otherwise necessary. As a result, human labor has been necessary to ensure accurate filling placement. This additional labor adds more cost to the assembly process, ultimately narrowing the profit margin for the ultimate product.
Consequently, known manufacturing processes for filled tortilla products are not completely adequate for some applications due to certain unsolved problems.
Broadly, this invention involves automated manufacturing equipment of the type utilized in an assembly line for food items. According to the invention, a filling preparation station produces defined lengths of meat or other filling materials for taquitos, enchiladas, burritos, and other rolled, folded, or wrapped tortilla foods. This station includes a smaller xe2x80x9cupperxe2x80x9d conveyor to carry filling segments, and a larger xe2x80x9clowerxe2x80x9d conveyor belt to carry tortillas. Other components include an extruder pump, cutter, and various sensors that produce output signals indicating tortilla and filling positions. According to the sensor outputs, a controller regulates operation of the filling conveyor, extruder pump, and cutter to produce and then accurately deposit segments of filling material upon tortillas as they pass by upon the lower conveyor belt. As needed, the controller (1) directs the filling conveyor to speed/slow/reverse, (2) directs the extruder pump to start/stop filling production, and (3) regulates the cutter to cut filling material as it emerges from the extruder pump.
More particularly, the controller performs dual roles, including (1) creating a filling segment of a desired size, and (2) accurately depositing the created filling segment upon a tortilla. To create the desired portion of filling segment, the controller awaits sensor outputs indicating arrival of a tortilla at a first designated site on the tortilla conveyor. Then, the controller starts the extruder pump after a prescribed time. Then, responsive to output signals indicating arrival of filling material at a first designated site on the filling conveyor, the controller completes a filling segment. Namely, the controller waits for a predetermined advancement of the upper conveyor belt (indicated by elapsed time or motor advancement) and then activates the cutter and stops the extruder pump.
To position the filling segment, the controller waits for arrival of a tortilla at a second designated site on the tortilla conveyor, and then starts a counter. Then, responsive to sensor outputs indicating arrival of the filling segment at a second designated site on the filling conveyor, the controller computes an offset between the filling segment and the tortilla. Using this offset, the controller then calculates a position correction profile to place the filling segment in predetermined relationship to the tortilla, and finally directs the motor to move the filling conveyor according to the position correction profile.
The foregoing features may be implemented in a number of different forms. For example, the invention may be implemented to provide a method to prepare food items utilizing a procedure such as that described above. In another embodiment, the invention may be implemented to provide an apparatus in the form of a filling preparation station of an assembly line. In still another embodiment, the invention may be implemented to provide a signal-bearing medium tangibly embodying a program of machine-readable instructions executable by a digital data processing apparatus to operate as discussed above. Another embodiment concerns logic circuitry having multiple interconnected electrically conductive elements configured to operate as mentioned above.
The invention affords its users with a number of distinct advantages. For example, the invention saves product costs and conserves resources because it generates filling segments of accurate size. Assembly lines no longer need to oversize products to guarantee a minimum size. In addition, the invention creates a more attractive product, preserves fryer oil, and saves labor costs by using automated means to deposit filling segments on corresponding tortillas. The invention also provides a number of other advantages and benefits, which should be apparent from the following description of the invention.